What is SIP (Session Initiation Protocol)?
Session Initiation Protocol (SIP) is a signaling protocol used to initiate, maintain and terminate multimedia communication sessions such as voice and video calls over the Internet. It is similar to HTTP but for real-time communications, serving as the backbone for most VoIP (Voice over IP) services. SIP manages these sessions but doesn't handle the media itself. Components of SIP include User Agent Clients (UAC) and User Agent Servers (UAS), which communicate through requests and responses to set up, modify and end sessions. This protocol is widely adopted for its scalability and integration with other protocols, supporting a broad range of communication services.